Prof. David Dunkerley - Honours Projects


Investigating whether the penetration of rainfall into soils is affected more by rainfall characteristics (intensity, duration) or by mulch and ground litter characteristics (composition, mass per unit area).

Supervisor: David Dunkerley
Field of Study: Hydrology
Support Offered: Will depend on EAE budgetary situation

Rainfall arrives at the ground with widely varying intensity and duration. Though it is routinely measured in the open (e.g in Bureau of Meteorology data), the fraction of rainfall that enters the soil and can support plant growth is often more important. This fraction is
affected both by the amount and intensity of the rain itself, and by the trapping,interception and evaporative losses that occur in mulch or ground litter.In this project we would record both rainfall (with tipping-bucket gauges equipped with data loggers) and soil moisture (using Theta probes) at a range of forest sites (e.g. Dandenongs, Gippsland, Otways, or other suitable field site). The goal would be to show how and at what rates soil moisture responds to rainfall. By experimentally manipulating the mulch or litter cover on test plots, and observing a range of rainfalls through the course of 6 months, the objective is to be able to show how rainfall and mulch/litter properties combine to determine the recharge of soil moisture. In this work, the rainfall would be measured under
the forest canopy, but above the litter/mulch layer. This is sometimes referred to as the net or effective rainfall, which is reduced compared to rain in the open owing to interception on the forest canopy.

For further information contact: David Dunkerley

How does storm pattern affect runoff from urban green surfaces?

Supervisor: David Dunkerley
Field of Study: Hydrology
Support Offered: Will depend on EAE budgetary situation

Urban green surfaces include domestic lawns and gardens, parks, playing fields, golf courses, and others. A number of these have been studied as sources of nutrients and fertilisers entering urban waterways and later, receiving waters. An aspect that is potentially important is storm pattern, which refers to where in the duration of rainfall the rain falls intensely, and when it falls less intensely. For instance, thunderstorms are often early-peak events, and these deliver less runoff than events where the rain is most intense later when soils have become wet. These storm patterns may change with climate change, and understanding the possible consequences of this for urban runoff will guide management responses.

This study would employ 6-min rainfall data collected by the BoM combined with runoff data collected by Melbourne Water or a city council.

For further information contact: David Dunkerley

Developing a new method for recording stemflow in trees and crop plants

Supervisor: David Dunkerley
Field of Study: Hydrology
Support Offered: Will depend on EAE budgetary situation

Stemflow is the movement of what has also been termed 'contact flow': water that drains from the foliage of a plant toward the ground, primarily by trickle-flow along the branches and stems. In some crops, such as some cereal crops, more than half of the water that reaches the soil and root zone does so as stemflow. Stemflow can also be problematic for land management, because it is erosive - this is a severe problem in Macadamia plantation cropping, for instance. In order to better understand the occurrence of stemflow, and its relation to controlling factors such as rainfall and phenology, improved recording methods are needed. Conventionally, stemflow collars are placed around the stem and the stemflow that is caught is held in a container for later measurement. This kind of device is problematic,especially because overflow is common in large storms, resulting in loss of data.
This project will seek to trial a new method, using chemical integration based on the weight-loss of blocks of sparingly soluble materials over which the stemflow drains.
These blocks can be reweighed periodically and their progressive weight loss converted to estimates of accumulated stemflow volume. Fieldwork at some convenient location would be integral to this project.

This could potentially be the Royal Botanic Gardens (Melbourne) or a suitable area of forest or possibly cropping.

For further information contact: David Dunkerley